Numerical simulations, also referred to as numerical analyses, are used in a wide field of different applications. In such analyses, at least one of elastic and plastic deformations of a part is simulated when the part is exposed to a load. The simulation results are e.g. used for the purpose of designing a tool required for forming a part having a desired shape, or for the purpose of inspecting a part with regard to its material behaviour under various levels of stress (e.g. for testing assembly of a part, or for testing crashworthiness of a part).
Examples for such numerical simulations are Finite Element Analysis (FEA) using meshed models, or other structural analyses using meshfree models.
With regard to the simulation of a defined forming process, when knowing the structure of the workpiece (raw part), the structure of the target formed part, the structure of a tool being used in the forming process, and the physical properties of the used material, a numerical simulation can validate whether the tool has the correct design required for arriving at the target formed part.
With regard to the simulation of a load inspection, a numerical simulation can analyse and check compliance to deviation tolerances of a part or subassembly when exposed to a specific load with a defined amount, defined direction, and a defined point of application.
In both exemplary cases, the according simulation creates flawed results which can be minimised with the involvement of a simulation-model which represents an actual produced part rather than a simulation-model which represents the target produced part.
While it is generally known to use such simulation-models basing on an as-built part, the way they are generated results in imperfect models. This is the case because measurement data of the as-built part are used as basis for the simulation-model. Since measurement data are mostly not coherent and/or consistent, they render an incompatible basis for generating a simulation-model so that these directly created models are very different in organisation and structure compared to the meshes generated by numerical simulation software from a CAD-model. In particular, said models generated based on the numerical representation may be noisy and may have missing areas of the surface that were missed in the measurement process.
The present invention therefore proposes an improved way to generate simulation-model which represents an actual manufactured part. Simulation-models generated by the method according to the invention are more complete and more “clean”, and therefore more suitable for numerical simulations, which therefore provide improved results.
A simulation-model generated by the inventive method may be used with any numerical simulation, such as a Finite Element Analysis or other structural analyses which simulate the deformation of featured parts and assemblies. Said numerical simulation may use meshed models (as they are used in FE-analysis) or unmeshed models (as they are used in new simulation approaches).
In order to provide an actual simulation-model, which represents the part as it has been actually formed, a target simulation-model of a (desired) target formed part is modified to confirm with a numerical representation (e.g. a measured point cloud) of the actual part. In particular, a simulation-model of the actual part may be achieved by matching and/or fitting the smooth and complete simulation-model of the desired part (generated by numerical analysis software) to the measured data representing the actual produced part.
An electronic representation of the actual part is, or is based on, a point cloud or a mesh captured from one of the many surveying sensors known in the art, e.g. white light scanners, blue light scanners, Coordinate Measuring Machines (CMM), 3D laser scanners, ultrasonic thickness tester, or Computer Tomography based scanning devices. Rather than trying to convert this point cloud or mesh of the actual part into a mesh that is compatible with numerical software, a model generated from the theoretical CAD-model of the target part is reshaped to match the point cloud. This results in a cleaner and more complete mesh.
For example, a clean Finite Element-mesh of an actual part is created by                measuring the as-built part with one of many measurement methods to generate a three-dimensional numerical representation of the as-built part;        providing or generating a clean simulation-model optimised for a numerical simulation software of the target part (e.g. derived from the CAD-model of the target produced part);        fitting this clean target FE-mesh onto the point cloud or mesh; this may include taking into account the errors both perpendicular to the part surfaces and also parallel to it; by this modification of the target simulation-model, an “actual” simulation-model is generated as it corresponds to the actual produced part;        
Several three-dimensional numerical representations or several actual simulation-models may hereby be averaged in order to achieve more statistical robustness.